Research themes

My research focusses on understanding deep learning from an empirical and scientific perspective, aiming to derive actionable insights that can improve its practical application. Major themes include:

  model interpretability via representation analysis

Deep learning works by transforming inputs to latent representations. Can we understand and describe the information stored in these latent representations?

• In Bhalla*, Oesterling*, Srinivas, Calmon & Lakkaraju (2024), we find that representations of vision-language models can be written in terms of a sparse linear combination of “concept” vectors that denote individual high-level semantic concepts; which we can use for dataset analysis and model editing
• In Bhalla, Srinivas, Ghandeharioun, Lakkaraju (2024), we propose to evaluate representation-based interpretability methods via their ability to control model behaviour. To facilitate this, (1) we unify 4 existing representation analysis methods as “encoder-decoder” methods, similar to sparse autoencoders; (2) we provide control-based metrics and datasets to evaluate these methods

  data-centric machine learning

Behaviour of machine learning models, including large language models (LLMs) depend critically on the datasets used to train them. Can we identify critical datapoints / data subsets that influence key model properties?

• In Ley, Srinivas, Zhang, Rusak & Lakkaraju (2024) we propose “generalized group data attribution”, a framework to extend arbitrary data attribution algrorithms to efficiently attribute to groups of training data points, yielding upto ~50x attribution speedups
• In Bordt, Srinivas, Boreiko & von Luxburg (2024), we study the problem of contamination of evaluation data into the pre-training data, and we find that such contamination does not automatically imply overfitting on the benchmarks. The primary confounding factor is the natural forgetting dynamics, due to which data seen early on during training may be forgotten by the end of training

  model interpretability via feature attribution

Machine learning classifiers often work by “looking at” a small number of important features present in the inputs. For example, a cat classifier only needs to identify “cat-like” features in the image, while ignoring all other features. How can we formalize this question of identifying important or salient features, and develop efficient algorithms to extract them?

• In Srinivas & Fleuret (2019), we observe that the outputs of ReLU NNs can be written exactly as the sum of layerwise gradients. We use this fact to define gradient-based saliency visualizations for such models
• In Srinivas & Fleuret (2021), we show that popular computer vision-based saliency approaches can be unfaithful to models, in that they produce attributions completely independent of model behaviour
• In Han, Srinivas & Lakkaraju (2022), we unify 8 popular feature attribution methods via local linear approximations of non-linear models
• In Srinivas*, Bordt* & Lakkaraju (2023) and Bhalla*, Srinivas* & Lakkaraju (2023), we identify model robustness as a key factor in producing faithful feature attributions. To quantify faithfulness, we define a notion of ground-truth feature attributions in terms of the signal a feature carries about the predicted label, formalized via a “signal-distractor” decomposition

  alternate notions of model robustness

Training adversarially robust models is hard. Are there alternate definitions of robustness that are both practically meaningful, yet easier to train for?

• In Srinivas*, Matoba*, Lakkaraju & Fleuret (2022), we propose an efficient algorithm to train deep models that are smooth, in the sense that they have a small Hessian everywhere. The resulting smooth models are competitive with adversarially robust models, have stable gradients, and maintain predictive accuracy
• In Han*, Srinivas* & Lakkaraju (2024), we propose average-case robustness as an alternative to the worst-case adversarial robustness, and develop methods to efficient estimate this quantity
• In Srinivas*, Bordt* & Lakkaraju (2023), we introduce the concept of off-manifold robustness, where models are robust only to perturbations of irrelevant “distractor” features – an aspect characteristic of Bayes Optimal predictors

  computational efficiency of deep models

Given a pre-trained deep model, how can we effectively identify and eliminate redundant neurons or weights while maintaining the model’s performance?

• In Srinivas, Kuzmin, Nagel, van Baalen, Skliar, Blankevoort (2022), we propose a state-of-the-art approach to train sparse neural networks, via incorporating a cyclical sparsity schedule which alternates between pruning and “unpruning” weights
• In Srinivas & Babu (2015), we propose a simple algorithm to identify redundant duplicate neurons and remove them from pre-trained models, without incurring accuracy loss, via a “surgery” step
• In Srinivas & Babu (2016) and Srinivas, Subramanya & Babu (2017), we propose an algorithm to automatically prune neurons / weights during training, but incorporating trainable multiplicative binary gates to neurons / weights

Apart from these broad themes, here are some cool miscellaneous projects I have worked on:

• gradient-based knowledge distillation: In Srinivas & Fleuret (2018), we propose to distill knowledge from a “teacher” to a “student” model by matching their gradients, which helps improve the sample efficiency of distillation

• certified robustness to LLM attacks: In Kumar, Agarwal, Srinivas, Li, Feizi & Lakkaraju (2024), we propose a certified defense to a certain class of adversarial attacks on LLMs, based on a simple “erase-and-check” procedure